Inductively coupled plasma (ICP) reactors generally form plasmas by inducing current in a process gas disposed within a process chamber via one or more inductive coils disposed outside of the process chamber. The inductive coils are typically disposed above the chamber and connected to a radio frequency (RF) power source.
Due to the configuration of the one or more inductive coils above the process chamber, process gases are typically introduced into the chamber from entry ports in sidewalls of the chamber. When RF current is fed to the inductive coils via a feed structure from an RF power source, an electric field generated by the inductive coils can form an inductively coupled plasma from the process gases.
However, the inventors have observed that process gases introduced from the side of the chamber can cause non-uniformities in the plasma formation within the chamber.
Accordingly, the inventors have devised an improved inductively coupled plasma process apparatus as described herein.